The first Kettle grandchild is born, so Kim's parents travel to see their grandchild. After worrying about making a good impression upon meeting Kim's parents, Ma finds herself a new nemesis. Kim's mother is a nut who takes over the Kettles' house with her views on hygiene. She hires a nurse for the baby and makes everyone, including Ma, where a mask around the baby. It is abundantly clear that Ma knows how to take care of children. That absurdity makes the situation all the more funny.
Kim's father befriends the Kettles and helps them when uranium is "discovered" on their old farm. With the newfound wealth is newfound trouble good for a few laughs.
Familiar faces and settings returned once again in Ma and Pa Kettle Back on the Farm . Rather than recycle all the old jokes, only a couple made it into the movie. The modern house is only used for one gag, and the radio in the old house is used again. Pa still casually uses dynamite with all the danger it brings. There was enough continuity to respect the prior films while creating a new adventure and introducing more characters.
With each movie in the series the sophistication of Ma Kettle becomes more and more apparent. Not only was she a vehicle for comedy, but for real human emotion. The balance was clearly a collaboration of everyone involved. Marjorie Main was given great scenes to work with. Despite being known for comedy, the Ma and Pa Kettle series had a subtle serious side as well.